WASHINGTON – President Donald Trump is spending part of his summer break pondering a pivotal event: A prospective report by Russia special counsel Robert Mueller.

In tweets and public statements, Trump and supporters are already responding to what they believe will be a written report by Mueller's team on its findings about the 2016 election, perhaps dropping as early as this month.

"This is the most one sided Witch Hunt in the history of our country," Trump said during a weekend tweet storm in which he raised more questions about a key event: His son's meeting in Trump Tower with a Russian lawyer he believed had political dirt on Democratic candidate Hillary Clinton.

The special counsel is also looking at whether Trump sought to obstruct justice in various ways, from the 2017 firing of then-FBI Director James Comey to repeated attacks on Mueller and his prosecutors.

As he plans to spend this week at his golf club in New Jersey, Trump must also consider a decision that could affect the timing of Mueller's report: Whether or not to provide testimony to the special counsel.

Mueller and his team of prosecutors and investigators have been close-mouthed about timing, but it doesn't appear their probe will end soon. The investigation has already resulted in the indictment of 19 people and three companies. Five of the people indicted – including three former members of the Trump campaign – have pleaded guilty to criminal charges.

...Why aren’t Mueller and the 17 Angry Democrats looking at the meetings concerning the Fake Dossier and all of the lying that went on in the FBI and DOJ? This is the most one sided Witch Hunt in the history of our country. Fortunately, the facts are all coming out, and fast!

What will we know? When will we know it?

When – or if – Mueller issues a report is a tantalizing mystery; his office has been leak-proof, and no one outside the investigative teams knows how he will play it.

"There's no way to know," said Randall Eliason, a former public corruption prosecutor who now teaches white-collar criminal law at George Washington University. "Anybody who says they know is just guessing."

Trump attorney Rudy Giuliani said Mueller has not told him anything about a report, but he believes prosecutors are already preparing a submission to the official who appointed Mueller, Deputy Attorney General Rod Rosenstein.

Giuliani, who said his team is preparing a counterreport, said he believes Mueller and his lawyers "want to wrap it up before September, or at the beginning of September." The reason, he said, is that Mueller won't want to be seen as interfering with the congressional elections coming this fall.

What role will the midterms play?

Republicans in Congress would probably breathe a sigh of relief if Mueller released his report now, while they’re out of town for an August break. That would give lawmakers a chance to respond with carefully worded press releases, rather than being put on the spot in person by congressional reporters scouring the halls of the Capitol.

Lawmakers would also be able to punt questions about what action, if any, Congress should take in response to the special prosecutor’s conclusions. The Senate will return from its recess on Aug. 15. The House will not be back until after Labor Day.

If Mueller does not report by Labor Day, he may wait until after the Nov. 6 vote. Prosecutors prefer to avoid taking action that could be seen as affecting an election, and many Democrats are still seething at the FBI's decision in 2016 to reopen and then reclose the Hillary Clinton email investigation less than two weeks before Election Day.

While candidates have traditionally feared an "October surprise" that could blow up their campaigns at the last minute, the growth of early voting means that bombshell news that hits anytime between September and Nov. 6 could change the election outcome, said Capri Cafaro, who teaches in the Department of Public Administration and Policy at American University.

"If you're in an early-voting state, revelations from the investigations could have an impact even if they happen in August or September," she told USA TODAY in May.

Some attorneys, however, say the election may not be as much of a factor to Mueller. Eliason noted that Mueller is investigating Russian election activity and that Trump himself is not on the ballot, so the Justice Department rule of thumb about timing and elections may not apply in this case.

Will Trump talk to Mueller?

As for Trump's possible testimony, Giuliani said that "we continue to talk" with Mueller's team.

"The president has been clear that he wants to interview. I will tell you his legal team is concerned," Trump attorney Jay Sekulow said Sunday on ABC's "This Week."

Giuliani said attorneys worry that prosecutors may set a "perjury trap" for the president if there are no ground rules in place. He reiterated that the president is eager to testify and said Trump has done nothing wrong.

“I think (special counsel Robert) Mueller will want to subpoena the president if he thinks it's necessary to get his testimony.”

David Kris

At some point, Trump will have to say yes or no, and Mueller can move forward – possibly with a report, possibly with an unprecedented subpoena of a sitting president who refuses to provide testimony.

Trump and attorneys say the special counsel lacks the legal authority to compel testimony from a sitting president and would likely challenge any subpoena in court. That would delay the investigation even further.

"I find it hard to believe the president will do the interview voluntarily," said David Kris, a former head of the national security division at the Justice Department.

Kris, a founder of the Culper Partners consulting firm, described Mueller as a by-the-book prosecutor who believes Trump's testimony is essential and is apt to go to court to get it.

"I think Mueller will want to subpoena the president if he thinks it's necessary to get his testimony," Kris said.

Giuliani and other advisers to the president have said Mueller doesn't need Trump's testimony to file a report. Citing thousands of documents supplied by the White House and interviews of Trump aides, they said Mueller already knows Trump's positions on the issues at hand.

How might Don Jr.'s meeting figure in?

Ongoing events may well affect Mueller's potential report. During his weekend tweet storm, Trump weighed in on a key aspect of Trump's inquiry, the June 2016 meeting that included, among others, Donald Trump Jr., and a Russian lawyer, Natalia Veselnitskaya.

In a tweet, Trump said, "this was a meeting to get information on an opponent, totally legal and done all the time in politics - and it went nowhere."

That story has changed over time. When news of the meeting surfaced more than a year ago, Trump dictated a statement sent out under his son's name claiming that the meeting was devoted to a discussion of international adoption policies.

The story changed with news that publicist Rob Goldstone, who who set up the meeting, told the younger Trump that the lawyer had derogatory information about Clinton. In any event, participants in the meeting, including Veselnitskaya, said no reports about Clinton were exchanged.

Fake News reporting, a complete fabrication, that I am concerned about the meeting my wonderful son, Donald, had in Trump Tower. This was a meeting to get information on an opponent, totally legal and done all the time in politics - and it went nowhere. I did not know about it!

Special counsel under attack

Trump's latest outburst could well provide another avenue for Mueller to explore for evidence of obstruction of justice.

In the past week, as attorneys negotiate a potential interview, Trump has launched his fiercest attacks yet on the special counsel.

Trump tweeted on Wednesday that Attorney General Jeff Sessions should "stop this Rigged Witch Hunt right now," Trump claimed that "Bob Mueller is totally conflicted" and his staff members "are doing his dirty work."

Posted!

A link has been posted to your Facebook feed.

Mueller leaves after briefing members of the Senate Judiciary Committee on the investigation into Russia's interference in the 2016 presidential election on Capitol Hill on June 21, 2017. Michael Reynolds, European Pressphoto Agency

Mueller arrives for a court hearing at the Phillip Burton Federal Building in San Francisco on April 21, 2016. He had been overseeing settlement talks with Volkswagen, the U.S. government and private lawyers for the automaker to buy back some of the nearly 600,000 diesel cars that cheat on emissions tests. Jeff Chiu, AP